Effects of altered sialic acid biosynthesis on N-linked glycan branching and cell surface interactions

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Title: Effects of altered sialic acid biosynthesis on N-linked glycan branching and cell surface interactions
Author(s): Pham, ND
Pang, P-C
Krishnamurthy, S
Wands, AM
Grassi, P
Dell, A
Haslam, SM
Kohler, JJ
Item Type: Journal Article
Abstract: GNE myopathy is a rare muscle disorder associated with aging and is related to sporadic inclusion body myositis (sIBM), the most common acquired muscle disease of aging. While the cause of sIBM is unknown, GNE myopathy is associated with mutations in UDP-GlcNAc 2-epimerase/ManNAc kinase (GNE). GNE harbors two enzymatic activities required for biosynthesis of sialic acid in mammalian cells. Mutations to both GNE domains are linked to GNE myopathy. However, correlation between mutation-associated reductions in sialic acid production and disease severity is imperfect. To investigate other potential effects of GNE mutations, we compared sialic acid production in cell lines expressing wild-type or mutant forms of GNE. Although we did not detect any differences attributable to disease-associated mutations, lectin binding and mass spectrometry analysis revealed that GNE deficiency is associated with unanticipated effects on the structure of cell-surface glycans. In addition to exhibiting low levels of sialylation, GNE-deficient cells produced distinct N-linked glycan structures with increased branching and extended poly-N-acetyllactosamine (polyLacNAc). GNE deficiency may affect levels of UDP-GlcNAc, a key metabolite in the nutrient-sensing hexosamine biosynthetic pathway, but this modest effect did not fully account for the change in N-linked glycan structure. Further, GNE deficiency and glucose supplementation acted independently and additively to increase N-linked glycan branching. Notably, N-linked glycans produced by GNE-deficient cells displayed enhanced binding to galectin-1, indicating that changes in GNE activity can alter affinity of cell-surface glycoproteins for the galectin lattice. These findings suggest an unanticipated mechanism by which GNE activity might affect signaling through cell-surface receptors.
Publication Date: 19-Apr-2017
Date of Acceptance: 1-Apr-2017
URI: http://hdl.handle.net/10044/1/49774
DOI: https://dx.doi.org/10.1074/jbc.M116.764597
ISSN: 0021-9258
Publisher: American Society for Biochemistry and Molecular Biology
Start Page: 9637
End Page: 9651
Journal / Book Title: Journal of Biological Chemistry
Volume: 292
Issue: 23
Copyright Statement: © 2017 by The American Society for Biochemistry and Molecular Biology, Inc. Final version free via Creative Commons CC-BY license (https://creativecommons.org/licenses/by/4.0/).
Sponsor/Funder: Biotechnology and Biological Sciences Research Council (BBSRC)
Biotechnology and Biological Sciences Research Council (BBSRC)
Funder's Grant Number: BB/F008309/1
BB/K016164/1
Keywords: Science & Technology
Life Sciences & Biomedicine
Biochemistry & Molecular Biology
INCLUSION-BODY MYOPATHY
PHOTO-CROSS-LINKING
SKELETAL-MUSCLE
RIMMED VACUOLES
DISTAL MYOPATHY
MASS-SPECTROMETRY
GENE-EXPRESSION
GNE MUTATIONS
STEM-CELLS
O-GLCNAC
N-linked glycosylation
aging
carbohydrate metabolism
galectin
sialic acid
Acetylglucosamine
Carbohydrate Epimerases
Cell Line
Cell Membrane
Humans
Mutation
Myositis, Inclusion Body
Polysaccharides
Protein Domains
Sialic Acids
Cell Line
Cell Membrane
Humans
Myositis, Inclusion Body
Sialic Acids
Carbohydrate Epimerases
Acetylglucosamine
Polysaccharides
Mutation
Protein Domains
06 Biological Sciences
11 Medical And Health Sciences
03 Chemical Sciences
Biochemistry & Molecular Biology
Appears in Collections:Faculty of Natural Sciences



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